b'19Citizen scientist involvement in water quality monitoring in the Upper Liffey and Barrow catchments: a case studyHegarty S1, Regan F1, ODowd P1, Brogan A1 and Clinton R11Water Institute, Dublin City University, Dublin, IrelandOver four days in September 2019, almost 600 citizens took part in a project to record and map the water quality of their local freshwater body in Ireland, with a focus on Leinster. The project was part of Earthwatchs Freshwater Watch Waterblitz programme, which in 2019 was rolled out to Dublin, Luxemburg and Paris as well as the Thames catchment in the UK. 202 water samples (53% of the samples) were taken throughout the Liffey Catchment over the four days, and the data fed back to the project leaders in real-time via an app that the participants had downloaded on their smart devices. The citizen scientists recorded nutrient levels (nitrates and phosphates) as well as conducting a visual survey of the waterbodies. This poster gives an overview of the results of the project for the upper parts of the Liffey and Barrow catchments, and includes information on the effectsof a heavy rainfall event on the water quality. It also discusses the importance of allowing localpopulations input into the collection of water quality data, and the importance of this oninforming public perceptions of water quality and water stewardship. 63'